1. Field of the Invention
The present invention generally relates to ceramic materials, and more specifically, ceramic bodies having inclusions of lubricious material and processes for forming same.
2. Description of the Related Art
While ceramic materials such as silicon carbide have found particular use in a variety of industrial applications due to properties such as corrosion resistance and wear resistance, such ceramics oftentimes do not have sufficient lubricity for some applications. Accordingly, particularly in the area of silicon carbide ceramic bodies, graphite loading has been incorporated in an attempt to improve the friction properties, particularly lubricity at elevated temperatures. Such ceramic components have found practical use in a variety of applications, including use as seals in dry environments and wet environments such as automotive pump seals.
Graphite-loaded silicon carbide bodies have been fabricated through various techniques. For example, such bodies have been formed by the so-called reaction bonded process, in which the precursor, typically carbon, is reacted with molten silicon during a high-temperature operation to form silicon carbide. Such reaction-bonded bodies typically additionally contain carbon graphite as a secondary phase that remains in the ceramic body following reaction.
Another technique utilizes a direct solid-state sintering process, typically involving pressureless or pressure sintering of a shaped body formed through powder processing techniques.
While the foregoing fabrication techniques and resulting graphite-loaded silicon carbide bodies represent improvements in ceramic components requiring a high degree of lubricity, a need continues to exist in the art for further improved ceramic components and processes for fabricating same.